Shale oil -- oil that is locked underground in shale and other rocks -- is commonly extracted through fracking, a process by which fluids are injected under high pressure into the rock to create fractures and facilitate the recovery of oil and gas. Alongside Saudi Arabia and Russia, North America is one of the top oil producers in the world, with the recovery of shale gas and oil from fracking having revolutionized the North American energy sector.
As a result, proper protection of carbon steel against corrosion is vital to achieve risk reduction in the handling, storage and transport of shale products, ensuring the safety of workers, communities and the environment. The storage of crude oil can create a very demanding chemical environment with regard to the integrity of storage tanks, pipes and vessels, requiring high-performing lining systems.
Tanks can experience aggressive conditions ranging from saline solutions, aqueous bacterial sludges, emulsion, low pH resulting in acidic environments and damage from high-pressure steam clean-outs to abrasion caused during maintenance and retrofits. Likewise, vessels and pipes are often subject to low-to-high pressure and a wide range of corrosive conditions and variable temperatures as part of their in-service lifetime.
Due to numerous in-service conditions, there is a clear need for careful assessment and consideration before pre-qualifying a lining for a tank, vessel, railcar or pipe. Not to do so would run the risk of an asset becoming corroded in just a few months, requiring replacement or even accidents or spills as a result of structural integrity loss caused by corrosion. Various methods of assessment are commonly performed to assess the suitability of a coating, from autoclave testing and electrochemical impedance spectroscopy (EIS) to visual inspection and adhesion testing.
After extensive testing and qualification, novolac epoxy coatings using polycyclamine curing agents have become linings of choice. For over three decades, highly cross-linked, thin-film, multicoat novolac epoxies were the mainstay for lining storage tank interiors, vessels and pipe spools, given their resistance to oilfield chemicals, as well as high temperatures and pressures, and their ability to "breathe" and withstand explosive decompression.
Given the demanding requirements in the oil and gas industry and the composition of sweet, sour and shale crude oils, the latest high-performing lining systems are in high demand. Many facility owners now utilize a single-coat, rapid-curing, solvent-free epoxy using a polycyclamine curing agent.
Enviroline 2405 from AkzoNobel is a remarkable, easy-to-use, solvent-free epoxy lining and is now in widespread use in the oil and gas industry. This coating is capable of being applied with single- leg spray equipment, typically at 12-25 mils dry film thickness. It exhibited the best performance out of nine linings in aggressive autoclave test conditions of 300 degrees Fahrenheit, 250 psig, 10-percent H2S and 10-percent CO2, as well as in shale oil, sweet or sour hydrocarbon and aqueous solutions. With a low surface energy and thus easy-to-clean characteristics, this single-coat epoxy has risen to prominence for lining tanks, vessels, pipe spools and railcar internals.
For more information, visit www. international-pc.com or email pcmar keting.americas@akzonobel.com.
